Segmented MEMS Resonator Layout for Higher Stable Output Current
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Solution Overview
Problem
MEMS resonators face challenges in achieving large output currents due to small capacitance and limitations in narrowing gaps and increasing bias voltage, leading to nonlinear resonance and instability, especially when input voltage is increased.
Innovation Solution
The MEMS resonator design includes multiple resonating units connected serially to the input port and parallelly to the output port, with identical mechanical resonance frequencies and mechanical coupling, using additional capacitive elements and impedance elements to distribute input voltage and maintain stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the gap between the output electrode and the vibrator is made small to increase output current, then the output current increases, but the manufacturing precision and stability deteriorate
Solution Approach 1:
The patent divides the single resonating system into multiple resonating units (first, second, and third resonating units) connected in series. Each unit has its own vibrator and electrodes, allowing the system to achieve high output current through parallel connection of multiple units rather than relying on a single unit with narrowly controlled gaps.
2Productivity
If the bias voltage is increased to increase output current, then the output current increases, but nonlinear resonance occurs and stability deteriorates
Solution Approach 1:
The patent divides the voltage application across multiple resonating units connected in series. Each unit receives a portion of the total voltage, allowing the system to operate at higher total voltages without any single unit experiencing excessive voltage that would cause nonlinear resonance or instability.
3Speed
If the vibrator size is reduced to micrometers or less to achieve high resonance frequency, then the resonance frequency increases, but the capacitance becomes small and output current decreases
Solution Approach 1:
The patent combines multiple resonating units with small capacitances in parallel connection at the output side. The individual small capacitances of each micrometer-scale vibrator are summed together, achieving large total capacitance and high output current while maintaining the high resonance frequency enabled by the small vibrator dimensions.
4Productivity
If multiple resonating units are added to increase output current, then the output current increases, but the device complexity increases
Solution Approach 1:
The patent designs multiple resonating units with identical or similar structures that perform the same function. Each unit consists of a vibrator, input electrode, and output electrode configured similarly, allowing for standardized manufacturing and simplified design while achieving high output current through their combined operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration expands the input voltage margin before nonlinear resonance occurs, ensuring stable operation and increasing output current while maintaining frequency stability and reducing noise.
Implementation Method 1
the capacitance made up by the vibrator 201 and the output electrode 205 (capacitance Co in FIG. 12B) is generally small
Implementation Method 2
The exciting force is derived from a varying electrostatic force due to a variation in potential difference between the input electrode 203 and the vibrator 201
Implementation Method 3
the resonance frequency (mechanical resonance frequency) of the vibrator, or a temperature sensor, a pressure sensor, a mass sensor, etc., each of which utilizes the resonance frequency of the vibrator
Data Source
AI summary
A MEMS resonator including: an input port which is applied with an input voltage; an output port which outputs an output current; and N MEMS resonating units (N being an integer greater than or equal to 2), the MEMS resonating unit each including a vibrator and being connected to the input port and output port, in which the N MEMS resonating units are serially connected to the input port.